Hello Gunnar,
Thanks for your inquiry.
The form is not sending emails both to the user and admin?
If yes, then please send me the form page link to check the issue, make sure that the email to user option is enabled.
If no, please make sure the email is not filtered to spam or junk folder of your email account. You can also try one of the following workarounds:
1. Try using another email address for From Email and Email to Send Submissions To options.
2. Perhaps your hosting does not have Sendmail enabled, which is required for mailing functions to work. Please contact your hosting provider and ask them to check this.
3. Alternatively, you can use an SMTP plugin, which will most probably resolve the problem.
You can try this plugin for example: https://wordpress.org/plugins/wp-smtp/
Setting an external SMTP server, such as GMail should work. However, GMail requires authentication. Please find the necessary details for SMTP setup below.
Mailer: smtp
SMTP Authentication: yes
SMTP Security: SSL
SMTP Port: 465
SMTP Username: your gmail full address
SMTP Password: your gmail password
SMTP Host: smtp.gmail.com
The SMTP plugin allows you to send a test email (https://i.imgur.com/S6C3Bux.png) and check if your server always sends the emails. Additionally, by setting up an external SMTP server, you will be able to use a mail server that’s quicker and more secure (e.g. Gmail). If you have received the email, then things are not that complicated and the issue is most probably connected with contact form plugin.`
